scholarly journals Effects of Postharvest Storage on Cyanide Content and Activity of Partially Purified Rhodanese from Bitter Cassava (Manihot Utilissima) Tubers

2020 ◽  
Vol 3 (2) ◽  
pp. 157
Author(s):  
Emmanuel Sina Akintimehin ◽  
Foluso Olutope Adetuyi ◽  
Kayode Olayele Karigidi ◽  
Raphael Emuebie Okonji ◽  
Clement Olomola Akinnubi

This research investigated the effects of postharvest storage on cyanide content and rhodanese isolated from bitter cassava (Manihot Utilissima) tubers. Cyanide content of freshly harvested sample, samples stored for 4 days and samples stored for 8 days were estimated by silver nitrate titration method. Rhodanese was purified using 80% ammonium sulphate precipitate and ion-exchange chromatography on CM-Sephadex C-25.Cyanide content from freshly harvested sample was 345.6 mg HCN/kg while 237.6 mg HCN/kg and 108 mg HCN/kg were obtained for samples stored for 4 days and samples stored for 8 days respectively. Specific activity of rhodanese from freshly harvested sample was 3.411 RU/mg while 5.92 RU/mg and 5.35 RU/mg were obtained for samples stored for 4 days and samples stored for 8 days respectively. The Km values of rhodanese for KCN were 3.18 mM, 2.40 mM, 0.25 mM for freshly harvested sample, samples stored for 4 days and samples stored for 8 days respectively. The optimum temperature from freshly harvested sample and sample stored for 4 days was 70 0C while samples stored for 8 days was 50 0C. An optimum pH of 4.0 was obtained from the 3 samples.Rhodanese play plausible role in cyanide reduction during the postharvest storage.

1985 ◽  
Vol 63 (11) ◽  
pp. 1160-1166 ◽  
Author(s):  
Pierre Gondé ◽  
Robert Ratomahenina ◽  
Alain Arnaud ◽  
Pierre Galzy

The exocellular enzyme β-glucosidase of Candida molischiana was studied. This strain is able to ferment soluble cellodextrins. The enzyme was partially purified by ion-exchange chromatography and gel filtration. The molecular weight of this enzyme was 120 000; its optimum pH was between 4 and 4.5 and its optimum temperature was 60 °C. This enzyme was active against different soluble glucosides and was inhibited by p-chloromercuribenzoate, gluconolactone, and glucose. A "glucosyltransferase" activity appeared in the presence of ethanol. The biosynthesis of the enzyme was constitutive but repressed by glucose.


2014 ◽  
Vol 8 (3) ◽  
pp. 64-69
Author(s):  
Shamam saady Abdulredha ◽  
Abdulkareem jasim Hashim ◽  
Abduljabar Abas Ali ◽  
Batool Imran Dheeb

Pleurotus ostreatus produced 2.93 U/mg of laccase in solid state fermentation (SSF) using barley bran as substrate under optimum conditions. The optimum SSF conditions were: pH 6.5; temperature, 25Cº; inoculums size 3.5 mm and moisture content, 1:1.5 w/v. Laccase was partially purified 8.29 fold with specific activity 17.5 U/mg by ion exchange chromatography after curd enzyme concentrated by dialysis against the solid sucrose. Partially purified laccase had an optimum pH of 6.5 and was stable in the pH range from 6.5 to 7.5. The optimum temperature was 45 Cº and it displayed considerable stability within the range 15 to 45 Cº with 1h incubation as well as The ability of partial purified laccase to decolorize of textile dyes showed that the blue H3R dye was completely decolorized in all concentrations within first min while yellow FG and red 3B dyes were decolorized in different percentage.


2021 ◽  
Vol 13 (2) ◽  
pp. 107-112
Author(s):  
C.F. Okechukwu ◽  
P.L. Shamsudeen ◽  
R.K. Bala ◽  
B.G. Kurfi ◽  
A.M. Abdulazeez

The most effective and acceptable therapy for snakebite victims is the immediate administration of antivenin which is limited by problems of hypersensitivity reactions in some individuals and its inability to resolve the local effects of the venom. The aim of this study was to isolate, partially purify and characterize phospholipase A2 from Naja Katiensis venom. Phospholipase A2 was partially purified via a two-step process: gel filtration on Sephadex G-75 and ion exchange chromatography using CM Sephadex, and subjected to SDS-PAGE analysis. From the results, the specific activity of the partially purified PLA2 decreased from 0.67μmol/min/mg in crude venom to 0.29μmol/min/mg after ion exchange chromatography with a yield of 5% and purification fold of 0.43. The optimum temperature of the purified PLA2 was found to be 35ºC and optimum p.H of 7. velocity studies for the determination of kinetic constants using L-a-lecithin as substrate revealed a Km  of 1.47mg/ml and Vmax  of 3.32μ moles/min/mg. The sodium dodecyl sulphate polyacrylamide gel electrophoresis of the purified PLA2 showed a distinct band with molecular weight estimated to be 14KDa. In conclusion, the present study shows that phospholipase A2 was isolated, purified and characterized. This may serve as a promising candidate for future development of a novel anti-venin drug.


1989 ◽  
Vol 263 (2) ◽  
pp. 477-483 ◽  
Author(s):  
J Deistung ◽  
R C Bray

A procedure is described for isolation of the pterin molybdenum cofactor, in the active molybdenum-containing state, starting from purified milk xanthine oxidase. The method depends on the use of anaerobic-glove-cabinet techniques and on working in aqueous solution, in the presence of 1 mM-Na2S2O4. SDS was used to denature the protein, followed by ion-exchange chromatography and gel filtration. The cofactor, obtained at concentrations up to 0.5-1.0 mM, was fully active in the nit-1 assay [Hawkes & Bray (1984) Biochem. J. 214, 481-493], with a specific activity of 22 nmol of NO2-/min per pg-atom of Mo (with 15% molybdate-dependence). The Mr, determined by gel filtration, was about 610, consistent with the structure proposed by Kramer, Johnson, Ribeiro, Millington & Rajagopalan [(1987) J. Biol. Chem. 262, 16357-16363]. At pH 5.9, under anaerobic conditions, the cofactor was stable for at least 300 h at 20-25 degrees C.


1984 ◽  
Vol 39 (3-4) ◽  
pp. 232-239 ◽  
Author(s):  
Gary Kuroki ◽  
Pauline A. Lizotte ◽  
Jonathan E. Poulton

Mature black cherry (Prunus serotina Ehrh.) seeds accum ulate high levels of the cyanogenic disaccharide (R)-amygdalin. Extracts from these seeds contain two β-glycosidases which have been identified and completely resolved by DEAE-cellulose ion-exchange chromatography. Amygdalin hydrolase hydrolyzed (R)-am ygdalin at an optimum pH of 5.5, releasing (R)-prunasin and D-glucose. This enzyme showed highest activity towards (R)-am ygdalin and failed to hydrolyze (R)-prunasin. linamarin, β-gentiobiose and cellobiose. A distinct β-glycosidase, prunasin hydrolase, displayed a pronounced preference for (R)-prunasin, hydrolyzing this cyanogenic monosaccharide at an optimum pH of 6.5 to mandelonitrile and D-glucose. Prunasin hydrolase was inactive towards (R)-am ygdalin, linamarin, and β-gentiobiose. Both enzymes showed significant activity towards the artificial substrates β-ONPGlu and β-PNPGlu but did not hydrolyze α-PNPGlu. In view of the pronounced specificity of these enzymes towards endogenous cyanogens, it is concluded that upon disruption of black cherry seeds (R)- amygdalin is catabolized to mandelonitrile in a stepwise manner (the sequential mechanism) by amygdalin hydrolase and prunasin hydrolase with (R)-prunasin serving as intermediate. Young fronds of Davallia trichomanoides are rich sources of (R)-vicianin (the β-vicianoside of (R)-mandelonitrile). A β-glycosidase, vicianin hydrolase, has been partially purified from frond extracts by ion-exchange chromatography. At the optimum pH of 6.0, this enzyme showed highest hydrolytic activity with (R)-vicianin, although both (R)-am ygdalin and (R)-prunasin could be hydrolyzed at approximately 15% of the rate observed with (R)-vicianin. It failed to hydrolyze β-gentiobiose, cellobiose, linamarin and α-PNPGlu. Closer exam ination revealed that (R)-vicianin and (R)-amygdalin were hydrolyzed at the aglycone-disaccharide bond (the simultaneous mechanism) yielding mandelonitrile and the respective disaccharides vicianose and β-gentiobiose


1996 ◽  
Vol 51 (5-6) ◽  
pp. 429-431 ◽  
Author(s):  
M.O. Ilori ◽  
O.O. Amund ◽  
O. Omidiji

Abstract A proteolytic enzyme produced by a cassava-ferment­ing strain of Micrococcus luteus was extracted and puri­fied 50-fold by gel filtration and ion exchange chromatography. The optimum pH for the enzyme was 7.0, the optimum temperature 25 °C, the apparent molecular weight 42 kDa and the Km value, 0.45 mg ml-1 with casein as substrate. The enzyme was stimulated by Ca2+ and Mg2+ but inhibited by Zn2+ and Co2+ ions. Other inhibitors were EDTA, KCN, citric acid and L-cysteine indicating the enzyme to be a metalloprotease.


1989 ◽  
Vol 44 (9-10) ◽  
pp. 883-885 ◽  
Author(s):  
Kenji Matsui ◽  
Yasushi Shibata ◽  
Tadahiko Kajiwara ◽  
Akikazu Hatanaka

Abstract In cucumber cotyledons, both C6- and C9- aldehyde were formed via hydroperoxide (HPO) lyase activity. Because it has not been elucidated whether these activities are attributed to one enzyme which can cleave both 13-and 9-HPO or to two or more enzymes each of which specifically cleaves 13-or 9-HPO , an attempt to separate HPO lyase activity was done. Ion exchange chromatography separated this activity into two fractions, one of which specifically cleaved 13-hydroperoxylinoleic acid and the other specifically cleaved the 9-isomer. 13-HPO-specific activity was most active at pH 8.0 and 9-HPO-specific one was at pH 6.5. SH -reagents inhibited both the lyases but to different extents.


2010 ◽  
Vol 15 (2) ◽  
pp. 99-105
Author(s):  
Y. Sri Manuhara

Isolation and characterization of β-1,3-endoglucanase from cabbage (Brassica oleracea var. capitata L.) have been done. It showed 40° C of optimum temperature, and optimum pH is 7. After the purification with hydrophobic interaction chromatography and ion exchange chromatography, it’s activity was increased. Based on SDS-PAGE analysis, β-1,3-endoglucanase have molecular weight around 48 kD. Antifungal activity of β-1,3-endoglukanase show that it has best inhibition zone on Fusarium solanii at extract from ion exchange chromatography.


Sign in / Sign up

Export Citation Format

Share Document